How close is this DBoys in size and configuration to what you're actually using? The RIS adds a fair bit of weight. DBoys is a lower end Chinese made copy of the Tokyo Marui M4S System, which is plastic bodied, unfortunately and therefore lighter. If you're just looking for something to drill with, it's a decent gun for the price. Unfortunately, all airsoft Armalites suffer from the same dimensional issues. Primarily the hand grip is noticeably fatter than a real one due to stuffing a motor in it and the mags are about 1/2" shorter than real ones due to the gearbox inside the gun. Other than that, it "works", hefts and "feels" like an Armalite. The charging handle does slide back, but doesn't do anything functional other than open the hopup adjustment port. The bolt release does nothing, just for show.
If you want exact in every possible detail, a Systema PTW is what you want, but they're about x10 what you're wanting to pay. Weight, balance, heft, hand grip and mags are the same dimensions as the real ones but the charging handle does nothing.